Apparatus for surfacing plastic bodies



0a 16, 1945. R. E. DAVIS 7 ,386 8 3 APPARATUS FOR SURFACING PLASTIC BODIES Filed Dec 3, 1941 2 Sheets-Sheet 1 0a, 16, 1945. v R. E. DAVIS 2,386,843

APPARATUS FOR SURFACING PLASTIC BODIES Filed Dec. 3, 1 941 2 Sheets-Sfieet 2 Patented Oct. 16, 1945 2,386,843 APPARATUS Fort sUnFAoINGrLAsTid BODIES Raymond E; Davis, Berkeley; Calif., assignor to Kalman Floor Qornpany, Inc., New York, N. Y.; a corporation of Delaware Attenuation Deceiiiber 3, 1941-, Serial No. 421,505

ill Claims.

apparatus int'eiided to be used rpr mus mg ra s s of Generate slabs; such as near slabs: 7

During recent'years there hay be'n sever-(ifs various types of mechariial'ly' averages nis'ms designed and intended to reduce t me minimumthe amount or in 'ua'i labor which must be expenses and the u eqin reda to re- 61106 to a true plane mi the desired siifi face to bl ticbo ies-sues as cbiiciet floors, Walks and roadways: A nuiiiber of; these mechanisms have into wid'essrese use; some particularly designed for use or'iroadways and others iiiriar'ily intended for nifilb'y'fient in the surfacingof fibers A li'fio'wn' we of mechanically operates seer g meets n'i'sin customarily rigs irig" member, amotor si-iibr'fiosd i'ifabfi' the worn-es gaging member for rotating the same, and a handle" which prevents IOfififidfi oinaefiiotoi casing and co'nstiinites a means; for moving th ii'n'f plem'rit over the Sui-race (if a eserete body the desired manner; I

In an earlier application flied by 6n the fifth day of June, 1940', series No 338,99lf; r'io'fir' Patent No. 2,28%);247, issues may 7,- 1942, I disclosed and claimed a stressing substrates or the type above general-1y described, but which includes as an entirely never feature, fi'ieclianisfii for imparting to the rotating tibilhgag'fng member high frequency vibrations so that the" plasticbody elow the assamtus is not any subjected to the actio'ii of are sets-ting disc, but is subjected to" high frequency vibrations: apparafiusis' highly effective arideiiabl's the user to properly surface a plastic body s'iidl-i as a sea: crete fioo'r a vastly improved :nannen by the aid of the rotating and vibrating disc extremely dry concrete rfiilirtilr' besiirfad'd, a' mixture having 's'iih' ailovt Water-cement ratio that it cannot be surfa'ic'ed by ordinary means or methods since itis impossible to laterally displace or horizbntally push material from the higher areas of the concrete onto thelowe'r areas.

The l'evelling'of the floor surface is broughtabout by vertically depressing the higher areas instead of laterally displacing these. areas and the concrete slab or" the like which is produced is of superior quality,- being denser and free" of voids. The surface is superior inasmuch as the novelmethod oflevelling the same results inbringing to the surface a relatively stiff- Paste of cement and fine sand, barely su-flicient inthick-- ness for the final trowelling by hand. The

proved method not only gives" 9; p r prbdgct but insures substantial savings in time and labor costs,- as comp-area with prior methods; I

The present invention relates particularly tot an improved a paratus for ca ry g out the method just described. accordance with the inven tion a work 'engaging member which comprises a substantially fiat disc has directly mounted thereon an eccentric which; when rotated at'high angular velonz'ity, imparts" to the i v br fi$ at high frequency, for instance, 5000 or more vibrations per ihi'nute. superposed upon the Work-engaging mer'nber is a motor carrier; yieldably supported so that the vibratory motion of the said mefnber will not be imparted to the n'iotor carrier, the motor carrier being, however, constrained to rotate with said member about a verticala'iiisi the motor carrier are threeniotofs; a motor for rotatin the" c rri r and with it the Work-engaging member and two additional motors, symmetrically lidsit-ined on opposite sides of the axis of rotation of the eccentric, for rota-ting the eccentric, each of the last two motors beingco nected to the eccentric by a flexible driving means such as a belt.

The motor carrier is' so formed that the two motors for driving the eccentric are positioned in close proximity to the work-engaging member, the center ofgravity of the apparatus as a whole being thus fii'ain'tained quite low. It will be appreciated that in the case of an apparatus of this type, which is intended to be moved manually from area to area over a 11001 by pull ing or pushing, it is much to be preferred that the center of gravity be maintained as low as possible to eliminate any tendency toward ov'erturning and to likewise prevent the leading edge or the disc from digging into the concrete.

All elements of the mechanism likewise have been constructed insuch manner as to secure maximum strength for a given weight of metal; the greatest simplicity, the most eiiicient; opera tion and the greatest ability to Withstand rough handling.

One embodiment of the invention which has been selected for disclosure by way of example is illustrated in the accompanying drawings in which- Figure l is a side view of the improved apparatus, partly in side elevation and in part broken away in order that various interior features may be observed;

Figure 2 is a section on line 2-2 of Figure 1;

Figure 3 isa section on line 3+=3 of Figure 2;

Figure 4; is a section on line 4 t of Figure 1;

ignated a wear-plate and which is preferably 'of hardened steel to offer increased.resistancetothe wear incident to rubbing of its lower surface-'- I against a relatively dry concrete mixture, and a' 3' base plate H, the wear-plate 18 being removably secured to the base plate H by bolts H so that it may be removed and replaced by a new plate when it becomes excessively worn. Directly mounted upon the base plate II is the eccentric device by means of which the base plate and 5 wear-plate may be vibrated at high frequency. This eccentric device includes a shaft l2. preferably formed in two portions connected by coupling l3, such shaft having fixed thereon adjacent the coupling |3,two belt pulleys indicated at I l-and |5,-respectively,.and the ends of the shaft, beyond pulleys l4 and I5, extending into cylindrical casings Hiand These casings are secured by straps l8 and bolts l9 to spaced parallel angles 26 which are in turn welded or otherwise suitably secured to base plate These angles extend substantially across the plate. II and also serve to stifien the work-engaging member. Filler plates Ziladirectly underlie casings l6 and I! and are welded to disc.

Coupling 3 is so constructed that the two portions of shaft l2 areconstrained to rotate together-at all times when the apparatus is in use even when the axesthereof become angularly disposed toeach other. By making the eccentric shaft in two parts flexibly connected together in this manner'it is possible to simultaneously drive two eccentricswhich are spaced apart, in such mannerthat they are always in the same phase, despite any warping of the work-engaging member. It-is' desirable to place the rotating eccentrics outwardly of the center of the work-engaging member so that the outer areas of .that member will be adequately vibrated,

as well as the central portions.

Within the housings or casings l6 and H, respectively, are anti-friction bearings -22 and 23 which encircle eccentric shaft I2 and support the same, and intermediate to each pair of bear ings 22 and 23 is aneccentric'weight 25, portions of which encircle the shaft l2 and are secured thereto by pins'26, constraining the weight to rotate with the shaft. The ends of cylindrical casings or housings I5 and H are closed'by plugs, as indicated clearly in Figure '7 and the casing, therefore, comprises a substantially oil-tight chamber. Each is-adapted to contain a small quantity of oil which, when the apparatus is in operation, will be beaten by the eccentric weight 25 into an oil fog, and the bearings will thus be maintained perfectly lubricated during the op- 'ovei the eccentric shaft|2i "of-the bridging portion 390 in turn supports a be observed that the motor carrier 30 includes the motor supporting portions 300, and 30b disposed just above and parallel to the base plate H and on opposite sides of the eccentric shaft, and an intermediate portion 30c which connects the portions 30a and 30b and bridges or arches The central part being operatively connected to the rotor of driving motor 3| by speed reduction gearing of known type. Driving shaft 36 is keyed to disc so thatwh'en'motor 3| is energized, the motor carrier as an-entirety will be revolved, although ata relatively low angular velocity due to the speed reduction gearing which is employed.

to the work-engaging member by resilient ele- Rotationof. the motor carrieris transmitted ments 3|3 ,which-are generally designated rubber springs. .Each such .element comprises a rubber block shaped as a short cylinder togetherwith bolts or the like securedto the ends thereof in any suitable manner by means of which the springs may beattaohed to adjacent parts such as the parallel webs of the U-shaped brackets 39 and 40. Brackets 39 are welded toportions 30d of the motor carrier and brackets 40 are suitably secured, as by welding, to-the base plate II. It will be observed from Figure 2 that there are four motorcarrier portions 30d and four groups of rubber springs-38, or sixteen in all. By this means the motor carrier and motors are mounted on'the work-engaging member in suchmanner that rotary motion is transmitted and at the same time all ofthe motors are shielded from vibration. l The-eccentric driving motors 32 and are disposed withtheiraxes in parallelism to the axis of the eccentric shaft |2 and each is mounted in such manner as to be bodily adjustable toward or away from such shaft? Thus motor 33 is shown to be mounted upon a plate 43 which is slidablymounted upon the underlying motor supporting portion 3lla of the motor carrier. Locking bolts 44, the lower ends of which are enlarged so as to lie in undercutslots formed in portion 30a areprovided-tosecure the motor in any position to whichit may-be adjusted-upon the motor carrier. This to-enable the operator to adjust, as by means of an adjusting bolt 45, the motor to a take up wear or slack in the driving belt |8 by It willbe observed by this arrangement that the means'for drivingthe eccentric is maintained at a very low elevation with respect to the workengagin member andsthe center of gravity of the entire apparatus thus kept as low as possible.

" When the apparatus is moved over the surface of a body of concrete, as by means of the operating' handle 5|! one end of which is connected to the casing of motor 3|, there is little or no tendency forthe apparatus to tilt, the handle being so disposed angularly with respect to the mechanism that the thrust? of the handle will pass approximately through the apparatus.

The meansfor supplying'x'electric current to the several motors may be as desired. Conven-H iently, electrical mains may pass down the hanthe' center of gravity of dle fl,being controlled byswitches 5| and 52 fixed on the upper end of the handle, one circuit con trolled by one of the switches being provided for the energization of the driving motor 3| and the second circuit, controlled by the switch 52, being provided to supply motors 32 and 33 with necessary current. By providing two circuits and two control switches an operator may, if he chooses, rotate the work-engaging member without vibrating the same or may vibrate said member without rotating it. As the motors 32 and 33 will revolve about the vertical axis of the apparatus when motor 3! is energized, it is necessary to provide slip rings such as indicated at 55 and 53, supported on insulating brackets 51 depend ng from the casing of motor 3|, brushes 58 and 59 being provided to take current from the slip rings and to supply each operating motor 32 and 33. A light casing or housing 60 has its lower edge afhxed to the periphery of base plate I l and encloses the motor carrier, eccentric, and eccentric driving motors, the casing top having a central circular aperture to receive the lower end of the casing of motor 3|. The housing or casing 60 prevents dirt or dust from settling upon the motor and operating parts of the enclosed mechanism, and also constitutes a safety shield enclosing the moving and electrically charged parts. The motors 32 and 33 are statically and dynamically balanced about the axis of motor 3|. If only one such motor is used a counterweight must be employed to maintain such balance.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. In an apparatus of the type described, in combination, a substantally flat plate for engaging the surface of a body of plastic material, an eccentric rotatably supported directly on said plate, a motor carrier above said plate and resiliently supported thereon, means connecting the carrier and plate for simultaneous rotation about an axis normal to the plate while permitting limited relative movement in the direction of said axis, a motor mounted on said carrier for rotating said carrier and plate, and a second motor mounted on said carrier and connected to said eccentric by a flexible driving means.

2. In an apparatus of the type described in combination, a substantially flat plate for engaging the surface of a body of plastic material, an eccentric rotatably supported directly on said plate, a motor carrier above said plate and resiliently supported thereon, means connecting the carrier and plate for simultaneous rotation about an axis normal to the plate while permitting limited relative movement in the direction of said axis, a vertically disposed motor mounted on said carrier, forrotating the carrier and plate, a horizontally disposed motor also mounted on the carrier, and driving means connecting the last mentioned motor to the eccentric.

3. In an apparatus of the type described, in combination, a substantially flat plate for engaging the surface of a body of plastic material, an eccentric rotatably supported directly on said plate, a motor carrier above said plate and resiliently supported thereon, means connecting the carrier and plate for simultaneous rotation about an axis normal to the plate while permitting limited relative movement in the direction of said axis, a motor mounted on said carrier for rotating said carrier and plate; two additional motors mounted on said carrier, on opposite sides of said eccentric and means flexibly connecting said motors and said eccentric.

4. In an apparatus of the class described, in combination, a substantially flat work-engaging plate, a motor operatively connected to the plate for rotating the same about an axis normal thereto, and means for vibrating the plate at high frequency, said means including an eccentric mounted on the plate for rotation about an axis parallel to the plate, and two motors positioned on opposite sides of the eccentric and operatively connected thereto by flexible means, said motors being resiliently supported on the plate for rotation therewith.

5. The combination set forth in claim 4 in which the eccentric comprises a shaft, an eccentric weight thereon, anti-friction bearings supporting the shaft on opposite sides of the eccentric weight, and a housing enclosing the weight and bearings, the shaft extending through an aperture in the housing end.

6. The combination set forth in claim 4 in which the two eccentric driving motors are dis-,

posed equidistantly from the axis of the eccentric and on opposite sides thereof, with the axes of the motors in parallelism with the axis of the eccentric and are operatively connected to the eccentric by belts.

'7. In a device of the type described, in combination, a motor carrier, three motors mounted thereon the weight of which is symmetrically distributed about the vertical axis of one of the motors, a work plate upon which the carrier is resiliently mounted and with which it is constrained to rotate, an eccentric mounted on the work plate for rotation about an axis which is intersected by the aforesaid motor axis when prolonged, and means operatively connecting the eccentric to two of said motors.

8. In a device of the type described, in combination, a work-engaging disc, an eccentric mounted on said disc for rotation about an axis parallel to the plane of the disc, a motor carrier resiliently mounted on the disc and connected thereto for rotation therewith, said carrier being arched over said eccentric and having m0- tor-supporting portions on opposite sides of said eccentric, a motor mounted on each such carrier portion, a substantially horizontal belt operatively connecting each motor to the eccentric, and means for rotating the disc, motor carrier, and elements supported thereon about a vertical axis passing through the axis of the eccentric.

9. The combination set forth in claim 8, in which said last mentioned means comprises a motor mounted upon the arch of the motor carrier, the rotor being operatively connected to said arch.

10. The combination set forth in claim 8 in which the eccentric comprises an elongated rotatable shaft having fixed on each end an ec centric weight.

RAYMOND E. DAVIS. 

